The present invention relates to production of T222 alloy. Developed in 1960, this tantalum base alloy provides corrosion resistance and high strength at elevated temperatures and has been used to make tubes and other mill products and fabricated parts contacting liquid metal in coolant systems. T222 comprises 9-10 w/o tungsten, 2.5-2.75 w/o hafnium, balance tantalum. It is preferred in some applications to add 0.1 w/o carbon to form hafnium carbides for added dispersion strengthening. The alloy can also be treated to create hafnium oxide for dispersion strengthening.
State of the art processes for making T222 involve complex melt cycles, including e.g. the Bechtel-Nevada process with two electron beam melts to alloy Ta, W followed by two vacuum arc melts (for alloying with hafnium) to produce ingots that can be broken down subsequently by extrusion and hot forging. The resultant material can thereafter be cold worked to produce wire, sheet and other forms.
It is the object of the invention to provide a T222 alloy product and process of making it characterized by higher yields and lower cost while substantially matching properties of the state of the art products.